The correct option is A 3^i+^j−^k
We have →r×→a=→b×→a⇒(→r−→b)×→a=→0
⇒(→r−→b) is parallel to →a
⇒(→r−→b)=λ→a
⇒→r=→b+λ→a
Similarly, the equation of the other line can be written as →r=→a+μ→b
For the point of intersection of the above two lines, we have →b+λ→a=→a+μ→b
⇒λ=μ=1
∴ The point of intersection is: →r=→a+→b=3^i+^j−^k